1. Technical Field
This disclosure relates to relay technology in a wireless communication network.
2. Related Art
In homes and offices, wireless LAN access points (hereinafter also called “access point”) have widely been used to connect wireless LAN clients (hereinafter also called “client”) such as personal computers and game machines to the network. Connecting the access point to a router enables the client to access the Internet via the access point and the router. The router is provided, for example, as a home gateway by an ISP (Internet Service Provider).
Portable (mobile) devices have been proposed as the access point. An example of such devices is a device (portable network connection device) having a functional part for wireless communication via a mobile communication network, e.g., 3G/HSPA (High Speed Packet Access) line, in addition to the functions as the access point. The user uses the portable network connection device to connect a personal computer to the Internet at an outside location. More specifically, by allowing the personal computer and the portable network connection device to respectively function as the client and as the access point, data can be transmitted from the personal computer to the portable network connection device. Additionally, by allowing the portable network connection device to function as the router, the portable network connection device can transmit data received from the personal computer to the Internet via the mobile communication network.
When the portable network connection device is brought back from the outside location and connected to the home network including the existing home gateway, two routers (i.e., devices having router functions) are simultaneously present in the home network. In this case, the client can not identify which of the routers is to be used as the gateway for data transfer with a device belonging to another network. There is accordingly a possibility that the client cannot normally transfer data with the device belonging to another network.
As described above, when the portable network connection device is brought outside, on the other hand, by allowing the portable network connection device to function as the router, the personal computer can access the Internet. Especially when the portable network connection device is used for connecting plural personal computers to the Internet, there is a need to enable the portable network connection device to serve as the router. Serving the portable network connection device as the router enables the plural personal computers to access the Internet via the portable network connection device by simply having an Internet-access service contract only for the portable network connection device with the ISP. In other words, it is not required to have an Internet-access service contract for each of the plural personal computers with the ISP. There is accordingly a need to enable the portable network connection device to serve as the router in the environment with no home gateway.
The function to be fulfilled by the portable network connection device in the presence of the home gateway and the function to be fulfilled by the portable network connection device in the absence of the home gateway have not been sufficiently considered. This problem may arise in company networks as well as home networks when a router is present separately from the portable network connection device.
Consequently, there is a need to enable the portable network connection device to serve adequately both in the presence of the router and in the absence of the router.